1. Field of the Invention
The present invention relates to a pair of swim goggles, and more particularly to a pair of swim goggles having buckle devices operated by pressing thereon for adjusting the length of a head strap.
2. Related Art
In wearing swim goggles it is necessary to adjust a head strap to fit a wearer's head. As is well-known, a method of adjusting the head strap is performed by two buckles respectively disposed on left and right sides of the swim goggles. Early design buckles aim to merely connect and position the head strap without considering an easy way to adjust the head strap. Once the head strap is to be adjusted, it has to be drawn back and forth many times. To avoid the inconvenience of adjusting the head strap, recent design buckles further include engaging devices used for limiting the head strap to move in only one direction. Each of the engaging device has an engaging arm capable of engaging tooth-shaped slots of the head strap so as to limit the head strap to be adjusted in only one direction during a period of engagement, that is, the head strap can only be drawn tightly. If the head strap is to be loosened, the engagement of the engaging arm with the head strap has to be released. Therefore, whether the engagement of the engaging arms of the above-mentioned buckles with the head strap relates directly to adjustment of the head strap.
Conventional buckles capable of limiting a head strap to move in one direction are varied according to operating methods, which are generally categorized into two major types: a press-type buckle and a push-type buckle. The operating method of the press type buckle is more compliance with the ergonomic. However, whatever type the buckle is, the engaging arm is required to cooperate with a flexible element in order to return to an engaging state after the engagement is released. Due to swim goggles are used in water, they cannot be made of metal material. Furthermore, the flexible element has to be tested repeatedly to meet flexibility requirements. Although the conventional flexible element is of sufficient flexibility, the structure of the conventional flexible element is rather complicated and is large in volume, which does not conform to a tendency towards light and thin design.